Electrical regulation.



W. SNEE & J. A. SNBE, JR.

ELECTRICAL REGULATION. APPLICATION FILED AUG. 28, 1914.

Patented Mar. 9, 1915.

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VOLTAG E WITNESSES WHEEL 5PE'ED VENTOR5 UNITED STATES PATENT OFFICE.

WILLIAM sum: AND Joiaiv A. SNEE, an, or WEST arazaina'rrr, PENNSYLVANIA.

ELECTRICAL REGULATION.

Specification of Letters Patent.

Patented Ma r. 9, 1915.

Application filed August 28, 1914. serial No. 859,138.

To all whom it may concern Be it known that we, WILLIAM SNEE and JOHN A. SNEE, Jr., citizens of the United States, and residents of West Elizabeth, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Electrical Regulation,

- of which the-following is a specification.

This application is, in part, a continuation of our application Serial No. 792,426, filed September'29, 1913.

The invention herein relates to generator volt-age regulation, and particularly to regulating voltage derived from a variable energy source, as a wind wheel, and one object is to utilize the state of charge of the battery for varying the generator-voltage with the battery charge and thereby maintain a voltage relation between the generator and battery.

A further object is to utilize variable energy, derived from the energy source from which the generator is driven, for maintaining such varying relation between the generator load and the wind wheel that the lat ter is caused to always rotate at its most eflicient speed for the wind prevailing at any given time, this variable energy control and the control effected by the state of charge of the battery cooperating in such manner as to maintain such relation between generator voltage, voltage of battery and speed and load of wind wheel as to secure maximum efficiency from all Winds of suflicient power regardless of varying velocities.

While the variable energy for driving the generator may be derived from winds, tides, water currents, etc., the primary purpose is to so apply it to power derived from the wind that the wind wheel will run atits best efliciency in all wind velocities, the generator load being automatically controlled by the speed of the Wheel, 2'. e., a force derived the tip speed of the wheel is seven-tenths that of "the "Wind velocity, aii dthatdeparture either way from this velocity ratio impairs the efiiciency of the wheel. But even though some different average speed ratio may be thought desirable, itis a purpose of the invention to maintain the most raverable speed ratio, whatever itmay be, in winds varying widely in velocity so that the greatest efficiency is always attained, this being accomplished by utilizing the generated elcctro-motive force and the state of charge of the battery for maintaining sue a favorable ratio.

An initial wind velocity is required for overcoming frictioni, excitation, etc., this requisite velocity varying slightly with variations in atmospheric humidity and density. \Vhen this necessary initial velocity has been attained the generator voltage should equal the battery voltage, no matter whatthe latter be. As the voltage of the battery varies with its state of charge, such variations are utilized for varying the excitation of the generator.

If the described voltage relation between the generator and battery were not modified, the voltages would bethe same at all speeds of the wheeland generator and no current would flow. Provision is therefore had for maintaining the generator voltage in excess ofthe battery voltage duringall wheel velocities which are greater'than that required to establish the initial relation. such excess voltage varying with the wind velocity and being sufiicient to. induce such a flow of current from generator to battery that the wheel is never overloaded or underloaded.

Apparatus for practicing the invention is illustrated diagrammatically in Fig. l of the accompanying drawings. Fig. 2 is a detail of a portion of the storage battery. Fig. 3 is a diagram illustrating variations in the battery voltage and in the specific gravity of the electrolyte. Fig. 4 is a diagram in which the generator output is plotted against windmill speed.

In the present illustration, the variable power is derived from a wind wheel A geared to an electric generator B.

C and C are the generator leads to an external circuit, and arranged in series with such circuit is anaccuinulator D. The latter may consist of a single storage battery or several batteries so connected as to be equivalent of a single battery.

For controlling the voltage two resistance devices E and l are included in the shunt G across the battery leads. Coil E constitutes the helix of a solenoid, the core H of which is connected to one end of lever J. This lever is adapted to be actuated by a spring K to compress a carbon pile resistance L in the shunt field winding 1) of generator B and the solenoid counteracts this spring under operating conditions presently to bedescribed.

The series resistance F is of step form with a series of mercury cups M connected to difierent portions thereof by wires N. Included in shunt G is the counterweighted lever 0 from which project the contacts P,

one for each cup M. Normally, the contact nearest the lever fulcrum closes the circuit through the mercury cup that directs the current through the whole length of resistance F. As the lever lowers and other contacts are entered in their cups corresponding portions of the resistance are eliminated.

the state of charge of the battery is utilized for thus varying the resistance of the voltage controller, in the adaptation here shown the specific gravity of the liquid element (1 of storage battery D being utilized by means of a hydrometer Q for oscillating lever 0, being connected thereto by wire 9. As the specific gravity of liquid d decreases with the depletion of the battery the resulting lowering of the hydrometer diminishes the effectiveness of resistance F.

' As the battery charge becomes depleted the resulting depression of the hydrometer decreases the resistance in series with coil E, and the resulting increased current fiow through the latter operates to raise core H against the pull of spring K and correspondingly decreases the compression of carbon pile L. This decreases the current flow through generator field b and correspondingly lowers the voltage. As the battery "oltage increases the upward movement of the hydrometer restores the resistance of coil F in series with coil E, correspondingly releasing core 'H to the pull of spring K,

thereby increasing the carbon pile com-v pression, and the resulting decreased resist ance in the field winding causes an increased voltage. The action of the hydrometer in raising and lowering is to cause the resistance F in series with coil E to be so varied that the generator voltage is always equal to that of the battery voltage when the generator has attained a predetermined minimum speed. This is accomplished by having the resistance F so subdivided and the successive contact P on lever O adjusted to y cooperate with their mercury cups at such tunes as to cause the generator voltage to conform to the battery voltage. In the diagram, Fig. 3, illustrating variations in battery voltage and specific gravity of the electrolyte during charge, the battery voltage is indicated by the curve 2-2. Variations in specific gravity are indicated by the line 33. As the greatest variations in voltage occur during the first and last portions of the charge it follows that resistance F must so operate that its greatest variations take place during those periods. By utilizing the gravity of the electrolyte for regulating the voltage of the generator, the regulating means are not affected by variations of charging voltage or current as would be the case if electrically operated.

The speed of the generator (or wind wheel) is utilized for so altering the voltage relation between the generator and battery as to induce a current flow into the battery. In the adaptation here illustrated a small supplemental generator R is geared to the main generator, and the current therefrom flows through a coil S wound on the spool which carries coil E and opposes the latter in such manner as to create the desired slight voltage difference in favor of the generator. The current output of generator R, while very small, varies in proportion to the power of the wind, so that as the mill speeds up the counteracting effect on coil E permits spring K to predominate sufiicientlyto cause the desired additional excitation of the generator field.

As the increase anddecrease of the output of generatorB, and hence the increase and decrease of the wind Wheel load, is determined at least in part by the speed faster or slower-01 generator R, and as the latter is geared to the Wind wheel and its speed is determined thereby, variations in the output of generator B will approximate a fixed relation to speed variations of the wheel resulting from variations in wind velocity. Variations in wheel speed cause variations in the output of generator R, which in turn cause variations in theoutput of generator B in approximate conformity with that characteristic of the wheel speed which varies its load proportionally to the cube of the wind velocity. Having ascertained the most advantageous ratio of wheel speed to wind velocity, and the maximum efficient output of generator B for all wind velocities and wheel speeds generator R- is so adjusted and utilized in connection with coil S that the effect on the constant-voltage ter to operate at its maximum efficiency, and any increase or decrease of wind velocity results in a proportionate increase or decrease in the output of generator R, but the efiicient relation remains substantially unchanged.

The diagram. Fig. 4, shows generator output plotted against windmill speeds. X is the point on the load curve denoting equality of generator and battery voltages, which point is attained after'f-rictional and excitation losses have been overcome. When generator voltage equals the battery counter E. M. F which latter is given the value X in the diagram Fig. 4, then useful work begins.

For a given generator speed, say 600 R. P. M., after the generator has supplied energy suliicient for excitation and other electrical losses it has attained a voltage equal to the battery voltage no matter what the latter, within operating limits, may be. When the generator speed increases, due to added wind impulse, auxiliary generator R energizes coil S, counteracting the effect of coil E, releasing lever J to the pull of spring K, compressing the carbon pile L, and correspondingly raising the voltage of generator B in conformity with curve X-V. By reason of this increased voltage, current is caused to flow from the generator through the .battery as shown by curve X-A. which denotes the amperes. The products of the ordinates of the curves X-V and X.A produce the curve XW which represents the maximum output in watts of the windmill.

To prevent the battery from discharging through the generator when the variable power prime mover stops, or when its speed is lower than will hold the generator volt age up to the battery voltage, an automatic switch is provided between the battery and generator which closes only when a generator voltage of suflicient strength has been attained. The switch may be variously embodied. As here shown, it consists of a shunt coil T connected directly across the battery leads through armature U pivoted at u, the switch circuit being closed through contact 1' when the switch is open, and the main circuit being closed through contact V when the generator potential is suilicient to energize magnet core t of coil T and attract the armature U thereto. A series coil \V in the battery lead is wound on the spool with coil T, and operates to maintain magnet core 1- energized after the switch has been closed and so long as the battery '01- tage does not exceed the generator voltage. iut when the generator voltage drops below the battery voltage coil T operates to deenergize series coil \V and the switch drops open bv gravity and remains open until there is sutficient generator voltage to close it.

No novelty is claimed herein for the several mechanical and electrical devices employed, excepting as they or their equivalentsare arranged or organized in a voltage controlling system, and hence it will be understood that the several devices may be variously constructed and embodied without departing from the invention.

While the invention is disclosed with special reference to its application to wind power, it will be understood that the underlying principles may be utilized for obtaining maximum efliciency from other sources of variable power.

We claim:

1.. The method herein described consistingin driving an electric generator by means of a wind wheel, utilizing the generated current for maintaining a predetermined relation between the generator load and the speed of the wind wheel, and utiliz ing the variations of the speed of the wheel for varying the load in conformity with. wheel speed variations as described.

2. The method herein described consisting in driving an electric generator by means of a wind wheel, utilizing the generated electrormotive force for tending to maintain the. potential of the generator substantially constant for all speeds of the latter above a given minimum, utilizing a force derived from the wind as the speed of the wheel increases for raising the generator potential, and so proportioning the said regulating forces as to cause the wheel to run substantially at a predetermined fraction of the wind velocity.

3. The method herein described consisting in charging a storage battery by means of a generator driven by a wind wheel, and governing the voltage of the generator by the conjoint action of the state of charge of the battery and the varying of the wind.

4. The method herein described. consisting in charging a storage battery by means of a generator driven by a Wind wheel, utilizing the generated electro-motive force and the state of charge of the battery and the intensity of the force derived from the wind for adapting the generator load to the speed of the wheel, and utilizing the state of charge of the battery for determining the approximate wind velocity at which current begins to flow.

5. The method herein described consisting in delivering to a circuit in series with a storage battery electrical energy from a generator driven by variable power, utilizing the state of charge of the battery for causing the generator potential to equal the battery potential whenever the generator runs at a given velocity, and utilizing the variable power for raising the generator potential as the speed of the generator exceeds such given velocity.

6. The method herein described consisting in delivering to a circuit in series with a storage battery electrical energy from a generator driven by a wind wheel, utilizing the state of charge of the battery for causing thegenerator potential t1 equal the battery potential whenever the generator runs at a given velocity, and utilizmg the velocity of the wind for maintaining a substantially constant relation between the work performed by the wheel and the available variable energy of the wind.

7. The combination of a. main electric generator, a Wind wheel for driving the generator, an electric circuit in series with a storage battery adapted to be charged from the generator, means actuated by the state of charge of the battery for equating the generator voltage to the battery voltage at a given wind wheel velocity, an auxiliary electric generator, and means actuated by the electro-motive force of the auxiliary generator for adapting the main generator load to the speed of the wind wheel.

8. The combination of an electric generator, a battery adapted to be charged therefrom, a wind wheel for driving the generator, variable controlling means operatively connected to the battery and actuated by the state of charge thereof, variable wind-actuated controlling means, and means actuated by the conjoint action of said two variable controlling means for controlling the voltage impressed upon the battery.

9. The combination of an electric generator having an electro-magnetic field, a wind wheel for driving the generator, a battery adapted to be charged from the generator, and means actuated by the state of charge of the battery for varying the resistance of the generator field.

10. The combination of an electric generator having an electro-magnetic field, a wind wheel for driving the generator, a battery adapted to be charged from the generator, and wind actuated means for varying the resistance of the generatorfield.

11. The combination of an electric generator having an electro-magnetic field, a wind wheel for driving the generator, a battery adapted to be charged from the generator, and two conjointly acting means for varying the resistance of the generator fieldone actuated by the state of charge of the battery and the other means actuated by force derived from the wind.

' 12. The combination of an electric generator having an electro-magnetic field, a wind wheel for driving the generator, a battery adapted to be charged from the generator, means actuated by the state of charge of the battery for varying the resistance of the generator field, and wind actuated means operatively connected to the means which is actuated by the state of charge of the battery for opposing the efli'ectiveness of the state-of-charge means.

13. The combination of an electric generator having an electro-magnetic field, a variable resistance in the generator field, means actuated by the state of charge of the battery for varying said resistance, and wind actuated means for opposing the resistance-varying action of the battery state of-charge means.

In testimony whereof we afiix our signatures in presence of two witnesses.

WILLIAM SNEE. JOHN A. SNEE, JR. Witnesses:

J. OLIVER PERCIVAL, F. J. KERRIGAN. 

